1. Field of the Invention
The present invention relates to a method for refilling liquid, which is preferably applicable to the ink supplying system of an ink jet recording apparatus, for example. The invention also relates to a liquid supplying apparatus, and a liquid jet recording apparatus.
2. Related Background Art
Technologies and techniques related to the liquid supply by use of liquid supply paths are utilized for various fields. As one example thereof, an ink jet recording apparatus can be cited. This apparatus records on a recording medium by discharging ink droplets from its recording head.
Since the ink jet recording apparatus records by discharging ink, there is a need for supplying ink to its recording head at all times to make it up as it is consumed for the intended operation. As methods for supplying ink to the recording head, there are known three methods given below according to a rough classification.
(1) A method for mounting an ink tank wherein the ink tank is detachably mounted on a carriage having a recording head installed on it, and the ink tank is connected to the ink supply inlet of the recording head at the same time.
As an ink tank used for this method, there is known a structure where a porous body, such as a sponge, is placed in it to store ink, with inclusion of an air conduit port to draw in the air from the outside for the smooth flow of ink during the printing operation.
(2) The so-called pit in method wherein a tank capable of storing a large amount of ink (hereinafter, referred to as a large tank) is provided, and at the same time, a head cartridge, which is formed by an ink tank and a recording head together, is mounted on a carriage so that ink is refilled by connecting the ink tank of the head cartridge with the large tank in a predetermined position to which the carriage travels.
(3) A method for refilling ink by means of a mechanism wherein a large ink tank is installed integrally with a recording apparatus main body, and ink path is formed by tubes or the like between the tank and a head cartridge, while arranging the mechanism on the ink path to supply ink to the head cartridge.
However, with a view to recording on a large-sized paper sheet or to refilling liquid for an apparatus that executes recording in a large volume, there are the problems given below with regard to each of the conventional techniques.
First, for the aforesaid method whereby to install a tank, the size of the tank is automatically limited because it should be mounted on a carriage, thus the storage of ink in the tank being restricted accordingly. This results in a problem that the cartridge should be replaced more frequently.
Second, for the aforesaid pit in method, ink remains tend to be varied with respect to a space (volume) to be filled in, and also, it is practically difficult to supply a specific amount of ink in good precision. In order to solve such problems, a system (an overflow system) should be provided for the collection of ink that has been supplied more than a predetermined amount or ink supply should be made extremely small in consideration of the anticipated variation thereof. For the former, however, the problem is that the apparatus should be made larger in consideration of its future use, and also, the invitation of wasteful consumption of ink is inevitable. For the latter, the problem is that along the increased frequencies of ink supply, the idle time becomes longer while recording is in operation, making its throughput lower after all.
Then, third, the method for refilling ink by a mechanism arranged on the ink path to supply ink necessitates ink to pass such mechanism. Therefore, it becomes difficult to remove dust particles or the like completely. Particularly, with use of a mechanism that supplies ink by squeezing the tube, component such as oil in rubber is dissolved, because the tube is always depressed. The dissolved oil adheres to the nozzles of a recording head. Such oil is solidified to bring about nozzle clogging or many other drawbacks.
With a view to solving these problems, the present invention is designed. It is an object of the invention to provide a liquid supplying method capable of reliably and easily executing liquid supply in the liquid supply paths, and also, to provide a liquid supplying apparatus therefor.
It is another object of the invention to provide a liquid jet recording apparatus capable of performing a stable recording without nozzle clogging of the liquid jet head by applying the aforesaid liquid supplying method and apparatus to the liquid jet recording apparatus provided with the liquid jet head.